The present invention relates to a freight and cargo door, hatch or gate with weight compensation, particularly, the invention relates to a weight balanced hatch, door or gate for the cargo space in an aircraft.
Gates, doors, hatches, or the like for vehicles, particularly aricraft, are usually provided to be opened from the inside, as well as from the outside, for easy and free access into the interior of the vehicle. These gates etc. are sometimes referred to as plug-type gates. The gates, doors or hatches of this type are usually very heavy and, in order to facilitate opening of them by operating personnel, certain aids are provided in a mechanical and/or electrical fashion for assisting in the opening and closing of the gates, doors or hatches. These assist structures are usually built into the gate itself or are generally a part of the vehicle.
Known mechanical opening and closing assist devices and structures are usually comprised of resilient elements in various configurations which, particularly during opening of the door, gate or hatch, aid in the opening movement and/or, in some fashion, balance or compensate the weight or mass of the door, gate or hatch. Electrical aiding and assist structures for this purpose usually work, also in conjunction with electromotors and electronic circuitry for the control of such a motor. Examples of this kind of arrangement are shown, for example, in European Pat. Nos. 105,082 or 114,324, or in German printed patent application No. 29 07 550.
These known structures for aiding and assisting opening and closing of gates, doors, hatches, or the like, are disadvantaged by the simple fact that an electric current and power supply is needed, and owing to the heavyness that is involved, the current needed is quite substantial. Moreover, it was found that due to the heaviness and complexity in the structure and design involved in such an electrically operated door, gate, or hatch mechanism, they are prone to interference and break-down, actually to a larger extent than mere mechanical devices.
Mechanical opening and closing structures using springs of various kinds, on the other hand, require additional features and equipments such as attenuating elements, particularly, if the support of the opening of the gate, door, or hatch, is not to involve or produce accellerated physical movement of the rather heavy parts. This is particularly necessary in order to avoid that operating personnel be endangered by too fast, for example, a swinging up of the gate. On the other hand, if the mechanical devices aiding in the opening and closing of such a gate, hatch or door, merely compensates the weight of the device being opened, for example, under utilization of a coiled spring, structures or the like, then the danger exists that, e.g. the spring twists and is no longer sufficiently operative.